在ASP.NET Web API中处理ModelState验证

Question

我想知道如何使用ASP.NET Web API实现模型验证。我有我的模型，像这样：

public class Enquiry 
{ 
    [Key] 
    public int EnquiryId { get; set; } 
    [Required] 
    public DateTime EnquiryDate { get; set; } 
    [Required] 
    public string CustomerAccountNumber { get; set; } 
    [Required] 
    public string ContactName { get; set; } 
} 

然后我有一个邮政行动在我的API控制器：

public void Post(Enquiry enquiry) 
{ 
    enquiry.EnquiryDate = DateTime.Now; 
    context.DaybookEnquiries.Add(enquiry); 
    context.SaveChanges(); 
} 

如何添加if(ModelState.IsValid)然后处理错误消息向下传递给用户？

Answer 1

关注的分离，我会建议你使用行为过滤模型验证，所以你不需要关心太多怎么办确认在您的API控制器：

using System.Net; 
using System.Net.Http; 
using System.Web.Http.Controllers; 
using System.Web.Http.Filters; 

namespace System.Web.Http.Filters 
{ 
    public class ValidationActionFilter : ActionFilterAttribute 
    { 
     public override void OnActionExecuting(HttpActionContext actionContext) 
     { 
      var modelState = actionContext.ModelState; 

      if (!modelState.IsValid) 
       actionContext.Response = actionContext.Request 
        .CreateErrorResponse(HttpStatusCode.BadRequest, modelState); 
     } 
    } 
} 

Answer 2

这样，例如：

public HttpResponseMessage Post(Person person) 
{ 
    if (ModelState.IsValid) 
    { 
     PersonDB.Add(person); 
     return Request.CreateResponse(HttpStatusCode.Created, person); 
    } 
    else 
    { 
     // the code below should probably be refactored into a GetModelErrors 
     // method on your BaseApiController or something like that 

     var errors = new List<string>(); 
     foreach (var state in ModelState) 
     { 
      foreach (var error in state.Value.Errors) 
      { 
       errors.Add(error.ErrorMessage); 
      } 
     } 
     return Request.CreateResponse(HttpStatusCode.Forbidden, errors); 
    } 
} 

这将返回这样的响应（假设JSON，但XML基本原理相同）：

HTTP/1.1 400 Bad Request 
Content-Type: application/json; charset=utf-8 
(some headers removed here) 

["A value is required.","The field First is required.","Some custom errorm essage."] 

当然你也可以建立你的错误对象/列出你喜欢的任何方式，例如添加字段名，字段的ID等

即使它是一个“单向” Ajax调用像一个新的实体的POST，你还是应该返回的东西给调用者 - 指示请求是否成功。想象一下你的用户将通过AJAX POST请求添加一些关于他们自己的信息的网站。如果他们试图输入的信息无效 - 他们如何知道他们的保存操作是否成功？

执行此操作的最佳方法是使用良好的旧的HTTP状态码，如200 OK等。这样，你的JavaScript就可以使用正确的回调（错误，成功等）正确处理失败。

下面是关于这种方法的更高级版本的一个很好的教程，用一个ActionFilter和jQuery：http://asp.net/web-api/videos/getting-started/custom-validation

Answer 3

也许不是你要找的，但也许是不错的人知道：

如果您使用的是.NET网络API 2你可以只需做下面的事情G：

if (!ModelState.IsValid) 
    return BadRequest(ModelState); 

根据模型的错误，你会得到这样的结果：

{ 
    Message: "The request is invalid." 
    ModelState: { 
     model.PropertyA: [ 
      "The PropertyA field is required." 
     ], 
     model.PropertyB: [ 
      "The PropertyB field is required." 
     ] 
    } 
} 

Answer 4

你也可以抛出异常，如记录在这里： http://blogs.msdn.com/b/youssefm/archive/2012/06/28/error-handling-in-asp-net-webapi.aspx

注意，要做到这一点文章提出什么，请记住，包括System.Net.Http

Answer 5

您可以使用属性从System.ComponentModel.DataAnnotations命名空间来设置验证规则。详情请参阅Model Validation - By Mike Wasson。

另请参阅视频ASP.NET Web API, Part 5: Custom Validation - Jon Galloway

其他参考资料

1. Take a Walk on the Client Side with WebAPI and WebForms
2. How ASP.NET Web API binds HTTP messages to domain models, and how to work with media formats in Web API.
3. Dominick Baier - Securing ASP.NET Web APIs
4. Hooking AngularJS validation to ASP.NET Web API Validation
5. Displaying ModelState Errors with AngularJS in ASP.NET MVC
6. How to render errors to client? AngularJS/WebApi ModelState
7. Dependency-Injected Validation in Web API

Answer 6

我不得不实施一个问题accepted solution pattern在我的ModelStateFilter总是返回false（以及随后400），用于actionContext.ModelState.IsValid某些模型对象：

public class ModelStateFilter : ActionFilterAttribute 
{ 
    public override void OnActionExecuting(HttpActionContext actionContext) 
    { 
     if (!actionContext.ModelState.IsValid) 
     { 
      actionContext.Response = new HttpResponseMessage { StatusCode = HttpStatusCode.BadRequest}; 
     } 
    } 
} 

我只接受JSON，所以我实现了一个自定义模型绑定器类：

public class AddressModelBinder : System.Web.Http.ModelBinding.IModelBinder 
{ 
    public bool BindModel(HttpActionContext actionContext, System.Web.Http.ModelBinding.ModelBindingContext bindingContext) 
    { 
     var posted = actionContext.Request.Content.ReadAsStringAsync().Result; 
     AddressDTO address = JsonConvert.DeserializeObject<AddressDTO>(posted); 
     if (address != null) 
     { 
      // moar val here 
      bindingContext.Model = address; 
      return true; 
     } 
     return false; 
    } 
} 

这一点我通过

config.BindParameter(typeof(AddressDTO), new AddressModelBinder()); 

Answer 7

这里我的模型后，直接注册，您可以检查一个

public HttpResponseMessage CertificateUpload(employeeModel emp) 
    { 
     if (!ModelState.IsValid) 
     { 
      string errordetails = ""; 
      var errors = new List<string>(); 
      foreach (var state in ModelState) 
      { 
       foreach (var error in state.Value.Errors) 
       { 
        string p = error.ErrorMessage; 
        errordetails = errordetails + error.ErrorMessage; 

       } 
      } 
      Dictionary<string, object> dict = new Dictionary<string, object>(); 



      dict.Add("error", errordetails); 
      return Request.CreateResponse(HttpStatusCode.BadRequest, dict); 


     } 
     else 
     { 
     //do something 
     } 
     } 

}

Answer 8

C＃

显示模型的状态误差一个

public class ValidateModelAttribute : ActionFilterAttribute 
    { 
     public override void OnActionExecuting(HttpActionContext actionContext) 
     { 
      if (actionContext.ModelState.IsValid == false) 
      { 
       actionContext.Response = actionContext.Request.CreateErrorResponse(
        HttpStatusCode.BadRequest, actionContext.ModelState); 
      } 
     } 
    } 

...

[ValidateModel] 
    public HttpResponseMessage Post([FromBody]AnyModel model) 
    { 

的Javascript

$.ajax({ 
     type: "POST", 
     url: "/api/xxxxx", 
     async: 'false', 
     contentType: "application/json; charset=utf-8", 
     data: JSON.stringify(data), 
     error: function (xhr, status, err) { 
      if (xhr.status == 400) { 
       DisplayModelStateErrors(xhr.responseJSON.ModelState); 
      } 
     }, 
.... 


function DisplayModelStateErrors(modelState) { 
    var message = ""; 
    var propStrings = Object.keys(modelState); 

    $.each(propStrings, function (i, propString) { 
     var propErrors = modelState[propString]; 
     $.each(propErrors, function (j, propError) { 
      message += propError; 
     }); 
     message += "\n"; 
    }); 

    alert(message); 
}; 

Answer 9

或者，如果您正在为您的应用程序错误的简单集合..这是我实现这一点：

public override void OnActionExecuting(HttpActionContext actionContext) 
    { 
     var modelState = actionContext.ModelState; 

     if (!modelState.IsValid) 
     { 

      var errors = new List<string>(); 
      foreach (var state in modelState) 
      { 
       foreach (var error in state.Value.Errors) 
       { 
        errors.Add(error.ErrorMessage); 
       } 
      } 

      var response = new { errors = errors }; 

      actionContext.Response = actionContext.Request 
       .CreateResponse(HttpStatusCode.BadRequest, response, JsonMediaTypeFormatter.DefaultMediaType); 
     } 
    } 

错误消息响应将如下所示：

{ 
    "errors": [ 
    "Please enter a valid phone number (7+ more digits)", 
    "Please enter a valid e-mail address" 
    ] 
}